A communications service provider, such as a telephone company (TELCO), offers voice and data transmission services over a communications network. Customers of the TELCO, commonly referred to as “subscribers,” may purchase as many communications services as they desire and equip their homes, businesses, or the like with communications equipment to utilize such services. Subscribers are responsible for proper operation of the communications equipment and the TELCO is responsible for proper operation of the communications network up to the electrical interface, commonly referred to as the “demarcation point,” between the TELCO wiring and the subscriber wiring. The demarcation point is the location where the subscriber wiring can be electrically disconnected from the TELCO wiring to determine whether a fault in the telephone line originates in the TELCO-owned equipment (including the TELCO wiring) or in the subscriber-owned equipment (including the subscriber wiring). As such, the demarcation point must be accessible to both the subscriber and the TELCO, and therefore, is typically located at the subscriber site within a network interface enclosure, such as a network interface device (NID) or a building entrance terminal (BET) mounted on an exterior wall of a home, office, apartment or other commercial or residential building.
The NID or BET houses at least one, and oftentimes, a plurality of termination modules for interconnecting the TELCO wiring and the subscriber wiring. Each termination module typically services a single telephone line and includes one pair of connection terminals for terminating the TELCO wiring and one or more pairs of connection terminals for terminating the subscriber wiring. The connection terminals provided on the termination module for terminating the TELCO wring are commonly referred to as “TELCO terminals” and the connection terminals provided on the termination module for terminating the subscriber wiring are commonly referred to as “subscriber terminals” or “subscriber pairs.” The TELCO terminals are typically located adjacent one end of the termination module in the NID or BET beneath a lockable cover that is accessible only to authorized TELCO personnel (e.g., an installer or a field service technician), and therefore, is commonly referred to as the “TELCO compartment.” Conversely, the subscriber terminals are typically located on the termination module within a portion of the NID or BET commonly referred to as the “subscriber compartment” that is accessible to both the TELCO personnel and the subscriber. The termination module typically further includes some type of electrical circuitry (e.g. half ringer) and/or electrical protection component (e.g., metal oxide varistor (MOV) or gas tube) that is electrically connected with the telephone line signal before the demarcation point. The electrical protection component, commonly referred to as a “protector,” may be integral with the termination module or may be located separately from the termination module, for example in the TELCO compartment. The subscriber pairs are accessed in most NIDs or BETs from above the termination module so that an installer or field service technician can readily terminate the subscriber wring to establish electrical connections with the termination module. Due in part to the limited amount of space within the subscriber compartment, only a small number of termination modules, and consequently, only a limited number of subscriber pairs, are available for connection to the subscriber wiring.
A known protected terminating device (PTD) is shown and described in U.S. Pat. No. 6,500,020 and available from Corning Cable Systems LLC of Hickory, N.C. After the PTD was introduced, subscribers and security system service providers began requesting electrical connections on the PTD for a security system burglar alarm. Burglar alarm connections must be made within the subscriber compartment of the NID or BET since the burglar alarm is subscriber-owned equipment that must be accessible to the subscriber and the security system service provider. According to a government regulation, the burglar alarm connections must also be made after the demarcation point so that the subscriber can electrically disconnect all subscriber-owned equipment, including the burglar alarm, to fault test the telephone line signal from the TELCO. Furthermore, the burglar alarm connections should be wired in series between the demarcation point and the first subscriber pair connected to the subscriber-owned communications equipment (e.g., telephone, telephone extension, facsimile, computer, etc.) so that the burglar alarm relay circuit can override the subscriber's communications equipment and seize control of the telephone line to send an alarm signal to the security system service provider. Due to the limited number of subscriber pairs available for each telephone line, it is undesirable to insert the wire pair leading to the burglar alarm and the wire pair returning from the burglar alarm into the first and second sets of subscriber pairs because the burglar alarm wire pairs would therefore occupy two of the four sets of subscriber pairs typically available on the PTD.
As with other termination modules, there is only limited access on the PTD to the wiring between the demarcation point and the subscriber pairs. As a result, the installer for the security system service provider may attempt to cut the wiring before the demarcation point, for example between the protector and the demarcation point, and physically splice the wire pairs leading to and returning from the burglar alarm into the telephone line. This field wiring solution is particularly likely when the protector is located separately from the termination module in the TELCO compartment. Electrically connecting the burglar alarm in series before the demarcation point, however, does not permit the subscriber to disconnect the burglar alarm to fault test the telephone line signal from the TELCO. Thus, in the event of a telephone line service problem, the subscriber cannot determine whether the telephone line fault is being caused by the spliced-in subscriber-owned burglar alarm or by the TELCO-owned equipment. As a result, the government regulation requiring isolation of all subscriber-owned equipment from the telephone line signal is violated. On the PTD termination module, it is also possible for the security system field installer to cut the line cord extending between the demarcation point and the subscriber terminals and to physically splice the wire pairs leading to and returning from the burglar alarm into the telephone line. While this alternate field wiring solution satisfies the government demarcation regulation, it is extremely difficult to accomplish given the limited space available on the PTD and presents further problems relating to management of the line cord, the line cord splices and any additional burglar alarm connections.
An existing solution that satisfies the aforementioned problems is illustrated in FIG. 1A and FIG. 1B. The subscriber bridge 20 portion of the PTD (shown in FIG. 2 and FIG. 3A at 15) includes a base 30, a pair of conductive contact elements 40 disposed within the base, and a base cap 50 positioned over the base and the contact elements. The contact elements 40 define a plurality of pairs of insulation displacement contact (IDC) type connection terminals 42, 44, 46, 48 for terminating the subscriber wiring. The connection terminals 42, 44, 46, 48 are accessible through wire insertion holes 52 provided on the base cap 50 and are commonly referred to as “subscriber terminals” or “subscriber pairs.” A cover 60 is rotatably attached to the base 30 and movable between a closed position and an opened position. The cover 60 has a pair of conductive contacts 65 disposed on the underside of the cover adjacent the forward end 62 of the cover. The contacts 65 are not visible in FIG. 1A, but are represented schematically on the wiring diagram of FIG. 1B. A line cord 70 containing a conductive line cord wire pair (represented schematically in FIG. 1B at 72) is electrically connected between the contacts 65 and the contact elements 40 disposed within the base 30. When the cover 60 is in the closed position shown in FIG. 1A, the contacts 65 engage corresponding conductive contacts 65′ (FIG. 1B) disposed in an RJ-11 jack on a PTD module base (shown in FIG. 3A at 18) to form a normally-closed switch that electrically connects the subscriber wiring and the TELCO wiring. When the cover 60 is moved to the opened position, the normally-closed switch is opened (as indicated by the broken lines in FIG. 1B) and electrically disconnects the line cord 70 (i.e., line cord wire pair 72), thereby disconnecting the subscriber wiring from the TELCO wiring. As such, the RJ-11 jack provides a demarcation point between the subscriber-owned equipment and the TELCO-owned equipment that allows a subscriber to determine whether a fault on the telephone line exists in the TELCO network.
Referring now to FIG. 1B, a conductive wire pair 12 from the TELCO network is electrically connected to a pair of connection terminals 14 provided on the PTD for terminating the TELCO wiring (i.e., TELCO terminals). The connection terminals 14 are electrically connected to the contacts 65′ disposed in the RJ-11 jack on the PTD module base 18. Normally (i.e., when the cover is in the closed position), the contacts 65′ are electrically connected to the corresponding contacts 65 disposed on the underside of the cover 60. The line cord wire pair 72 is therefore electrically connected between the contacts 65 and the contact elements 40 disposed within the base 30 of the subscriber bridge 20. The contact elements 40, however, are physically separated into first contact elements 40a defining first subscriber pair 42 and second contact elements 40b defining the remaining subscriber pairs 44, 46, 48. Thus, the first subscriber pair 42 is electrically isolated from the remaining subscriber pairs 44, 46, 48. A conductive wire pair 82 leading to a burglar alarm relay circuit 80 is electrically connected between the first subscriber pair 42 and a pair of conductive contacts 85 disposed on the burglar alarm relay circuit. A conductive wire pair 84 returning from the burglar alarm relay circuit 80 to the subscriber bridge 20 is electrically connected between the second subscriber pair 44 and a pair of conductive contacts 85′ disposed on the burglar alarm relay circuit. Conductive wire pairs 96, 98 leading to subscriber-owned communications equipment, such as a telephone, telephone extension, facsimile or computer, are terminated to the third subscriber pair 46 and fourth subscriber pair 48, respectively, remaining on the subscriber bridge 20.
The contacts 85 are electrically connected to the corresponding contacts 85′ to form a normally-closed switch. Accordingly, when the cover 60 is closed and contacts 65 engage contacts 65′, the telephone line signal from the TELCO network travels along the line cord wire pair 72 to the contact elements 40a that define the first subscriber pair 42. The telephone line signal then travels along the wire pair 82 through the contacts 85 and 85′ and along the wire pair 84 to the second subscriber pair 44 defined by the contact elements 40b. As a result, the wire pairs 96, 98 leading to the subscriber-owned communications equipment that are terminated to the third and fourth subscriber pairs 46, 48, respectively, are electrically connected to the telephone line signal. When the cover 60 is opened and contacts 65 disengage from contacts 65′, the line cord wire pair 72 is electrically disconnected from the TELCO network. As a result, the wire pairs 82, 84 leading to and returning from the burglar alarm and the wire pairs 96, 98 leading to the subscriber-owned communications equipment are electrically disconnected from the telephone line signal. Thus, the demarcation point (i.e., the normally-closed switch defined by contacts 65 and contacts 65′) isolates all of the subscriber-owned equipment, including the burglar alarm, from the TELCO network to permit the subscriber to fault test the telephone line signal. While this field wiring solution satisfies the government demarcation regulation, isolating the first subscriber pair 42 from the remaining subscriber pairs 44, 46 48 must be accomplished in the factory at the time the PTD is manufactured and assembled. Unfortunately, the current design of the PTD does not readily permit the first subscriber pair 42 to be physically separated from the remaining subscriber pairs 44, 46, 48 and separately retained within the base 30 of the subscriber bridge 20.